Reliability and Availability Modeling of non - repairable and repairable Systems with Failure Interdependency between Components Based on State-Space Representation

In the field of system reliability and availability analysis, it is usually assumed that the components are independent despite the fact that in reality systems may have items with interdependent failures. Independent failure analysis will lead to unrealistic results and may have a limited usage for practical purposes. The motivation of this paper is to consider dependencies on failures between components based on control engineering points of view and state-space representation in order to have more accurate reliability analysis which merits to be highlighted specially for the systems whose failures may lead to high risks. First, considering independent items, differential equations for reliability or availability of each item are written, then dependent failure rates are included by forming state-space representation models. By solving state-space equations of the model, reliability or availability function of each component is extracted which can be used to compute the reliability or availability function of the overall system with dependent subsystems based on their relations. Thoroughness of the approach presented for reliability and availability analysis of different integrations is its forte. The introduced procedure is used for some examples and its efficiency reveals the impact of failure dependency between items on the global system’s reliability and availability.